Tube rolling mill



19441 M. ROECKNER ETAL 2,224,487

TUBE ROLLING MILL v Filed May 28, 1938 2 Sheets-Sht 1 Dec. 10, 1940. ROECKNER AL 2,224,487

TUBE ROLLING MILL 2 Sheets-Sheet 2 Filed May 28, 1

I J: Several, y M 9W f Patented Dec. 10, 1940 TUBE ROLLING m Martin Roeckner and Jos Sever-in, Mulheim-onthe-Ruhr, Biihrenwerke Germany assignors to Deutsche Germany,

Aktiengeeellschaft, Dusseldorf,

Application May 28, 1938, Serial No. 210,123 In Germany July14, 1937 3 Claims.

This invention relates to a tuberolling mill for producing seamless tubes. It is known to produce tubes by subjecting a hollow block to the action of several pairs of rolls which are arranged around the block at a certain distance from the axis ofthe hollow block, one-roll of each pair of rolls acting on the inner side and the other on the outer side of'the wall of the block. The rolls have different profile developments by which a groove is cut in the material of the hollowblock by the first pair, this groove being widened by the next following pair so that a portion'of the material divided oif by the first pair is gradually drawn out towards one end of the hollow block. The axes of the rolls are at an incline to the axis of the hollow block and thus not only exert a deformation, elongation, but also a feed movement like a. worm gear. However, the feed movement of the hollow block takes place only at the commencement of the deformation. Now it has been found objectionable, that the hollow block to be rolled has to be pushedby some external auxiliary means between the rolls which have to carry out the deformation work. For overcoming this 25 objection it has been proposed, to provide the rolls at the feed end with a relatively long slightly tapering portion which is intended to better draw the material into the rolls. Another proposal is,

to taper that end of the hollow block which is 30 under all circumstances, a displacement of the hollow block in longitudinal direction.

In these known proposals it is consequently necessary to specially shape either the rolls or the 5 hollow block. Another roll arrangement is proposed, according to the invention, which allows a perfect drawing in of the hollow blocks by the rolls, without it being necessary to alter the or-' dinary shape of-the rolls. or of thehollow blocks. Consequently, the ordinary blocks with the usually smooth out edge can be rolled without difficulty. This is attained in that according to the invention the rolls are mounted so that they can yieldingly shift in a longitudinal direction to such 45 an extent that when drawing in the hollow block,

the ribs of several successively acting rolls are adapted to lie in front of the block whereby the working or drawing of the ribs into the hollow block is insured. This can be attained by displacing the rolls-in the longitudinal axial direction against the action of springs or weights, this displacement being moreover adjustable The normal rolling operation or process is also favorably influenced by. said yielding capacityof the 55 rolls.

pushed into the rolling mill, so as to facilitate Referring to the drawings:

Figures 1 and in show, for a. clear understanding of the distinction between the known art and the invention, working rolls heretofore used; Figure 1 being a side elevation and Figure la a sectional view taken on the line A-B of Figure 1.

Figure 2 is a side elevation of one of the rolls and showing the manner in which said roll can be displaced on its axis against the action of a spring. 7

Figures 3 and 4 are side elevational views of constructional examples for regulating the extent of the longitudinal displacement of the rolls.

- Figs. 5, 6 and"? are diagrammatic views showing the various stages of the rolling operation, carried out with the use of the rolls shown and described in conjunction with Figs. 2, 3 and 4.

In the known process, as illustrated diagrams matically in Figs. 1 and 1a, the inconvenience exists that the hollow block is not gripped by the rolls l-l, 2-2, 3-3. This is due to the following reason. When the slightly tapered portion of the rolls first grips the block and commences to draw it in, the block first encounters the ribof the roll I which tends to arrest the block. However, it overcomes this obstacle and moves on until it encounters the rib of the roll 3 which tends to arrest the block. As all the compressing ribs are situated on a helical line; the block in order to strike against the ribs of the different rolls must shift a short distance from'rib to rib. This short distance, however,-does not allow the shaping of a recessed portion of material. The first rolls have no grip behind their ribs and the block can consequently not move on.

With the roll arrangement according to theinvention (Figs. 2, 3 and 4) that is'when the rolls are movable in the direction of their longitudinal, axis, one roll can roll into the block after the other, in that owing to its inclined. position it shifts forward, whereas thefollowing rolls are pushed backwards against the action of the spring 4 (Fig. 2) by the block and thus suificient space-is produced between the. ribs of the first and second rolls, whereby a material portion of the block in the space between each roll will be gripped and drawn in between the rolls. The

longitudinal displacement of the rolis is prefer- 'ably eifected by the action of the, hollow block pressingthereagainst, and as shown in Fig.2, 5

said rolls are displaced on their 'axesagainst the springji This displacement. of-the rolls is ad-. justable according tothe constructions illustrated ineitherFlgstior-i. Thismaybeeflectedas shown in Fig. 3, by connecting. the roll with an externally screw threaded sleeve 5 provided with a worm wheel 6 adapted to be actuated by a worm I. By actuating the worm I, the roll may be adjusted in a position toward or away from the spring 4, depending on the amount of longitudinal displacement desired for the rolls.-

Another manner of adjusting the longitudinal displacement of the rolls is shown in Fig. 4,'

wherein the roll .bearings are carried in brackets 8 which are shiftable by a spindle 9 with screw thread l so that the rolls are shifted in the direction of their longitudinal axis.

Referring now more particularly to Fig. 5, this shows diagrammatically the movement of the rolls relatively to the hollow block when the front edge of the'hollow block bears against the rib of the first roll.

Fig, 6 shows diagrammatically the hollow block when the latter has been drawn forward to such an extent that its front edge bears against the rib of the third roll, the illustration in this view in. full lines of the rolls l and 2 shows these rolls in the position which they occupy when their ribs have been drawn into the surface of the hollow block. The illustration in dotted lines in Fig. 6 shows the position of the rolls I and 2 when they have not been drawn into the block, but are pushed back in their longitudinal direction by the front edge of the hollow block against the action of the spring shown in Fig. 2.

. Fig. I shows diagrammatically the position of the rolls during the normal rolling operation after all the rolls have been moved back into their forwithout departing from the scope of the inven-' tion. J

It is to be noted that the profile development of the working surfaces of the second pair of rolls and each successive pair of rolls have for their object to participate in the deformation and elongation of the portion of the material divided of! in the form of a rib of the hollow block until the disappearance of the rib and the formation of the smooth cylindrical tube wall which is however thinner than that of the hollow block which lies in front of the first pair of rolls.

v Weclaim:

1. A rolling mill for rolling hollow blocks into seamless tubes by elongation chiefly in the axial direction, including several pairs of ribbed rolls inclined to the axis of the hollow block and adapted to form helical lines on the surface of said hollow block; said rolls having successive profile developments so that each following roll further works the part of the hollow block already worked by the preceding roll, said rolls being displaceable in their longitudinal direction to such an extent that when drawing in the hollow block, the ribs of several successively acting rolls are adapted to lie in front of the block so that the yielding capacity of the rolls facilitates and including means for regulating the longitudinal displacement of each roll.

- MARTIN ROECKNER.

JosE SEVERIN. 

